Characterization of adsorption trends of NO2, nitrite, and nitrate on MgO terraces

Miletic, Marina; Gland, John L.; Hass, K. C.; Schneider, William F.

doi:10.1016/j.susc.2003.09.040

Cited by 18 publications

(9 citation statements)

References 35 publications

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“…i.e., it is effectively able to extract enough charge from RS (ox.) surface to form sorbed nitrate than in case of nitrite [17].…”

Section: Kinetic Studies Of Anions Adsorptionmentioning

confidence: 92%

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Hanafi¹,

Azeema²

2016

J Environ Anal Toxicol

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Rice straw (RS) has been activated using Na 2 CO 3 . Activated carbon samples (ARSC) were characterized using N 2adsorption, elemental analysis, surface fractional dimension and pore volume to support the adsorption of nitrate and nitrite ions. The effects of various parameters such as solution pH, adsorbent concentration, contact time, temperature and initial nitrate and nitrite concentrations were examined. Various kinetics models including the Pseudo-first-order, Pseudo-second-order and intra particle diffusion models have been applied to the experimental data to predict the adsorption mechanism. The thermodynamics constants of the adsorption process, viz. ΔH o , ΔG o and ΔS o were evaluated. The results showed that the adsorption of nitrate and nitrite ions onto activated carbon was exothermic and non-spontaneous. The adsorption data followed second-order kinetics supporting that chemisorption process was involved. The obtained results show that ARSC can be used as an effective and natural low-cost adsorbent for the removal of nitrate and nitrite anions from wastewater.Schematic diagram for preparation of activated carbon produces from rice straw.

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“…i.e., it is effectively able to extract enough charge from RS (ox.) surface to form sorbed nitrate than in case of nitrite [17].…”

Section: Kinetic Studies Of Anions Adsorptionmentioning

confidence: 92%

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Hanafi¹,

Azeema²

2016

J Environ Anal Toxicol

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“…Another study on the adsorption of NO 2 on TiO 2 also gives evidence for the formation of nitrate although with a different mechanism involving disproportionation of NO 2 on the metal’s surface and the interaction of NO 2 with oxygen vacancies . Regardless of the kind of metal oxide used, the nitrite and nitrate are expected as the products of surface reactions and such surface features as oxygen vacancies , or OH groups − were indicated as the most important for the retention process.…”

Section: Introductionmentioning

confidence: 99%

“…Metals and metal oxides have also been extensively studied in the processes of environmental remediation. The group includes ZnO, MgO, TiO 2 , CeO 2 , and Fe 2 O 3 , among others. Underwood and co-workers provided evidence for the formation of surface-bound nitrite and nitrate species after the adsorption of NO 2 on TiO 2 , Al 2 O 3 , and Fe 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

Interactions of NO₂ with Zinc (Hydr)oxide/Graphene Phase Composites: Visible Light Enhanced Surface Reactivity

2012

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Composites of zinc hydr(oxide) with either graphite oxide or graphene (ZnGO/ZnGr) were obtained using an in situ precipitation method. The surface properties were studied using Fourier transform infrared spectroscopy, X-ray diffraction, thermal analysis, potentiometric titration, and adsorption of nitrogen. The materials were exposed to NO 2 to evaluate their suitability as adsorbents of toxic industrial compounds at ambient conditions. The highest NO 2 adsorption capacities were found on Zn(OH) 2 and its composite with graphite oxide either in an as-received form or heated at 600 °C. In the majority of cases zinc nitrates were found as the main reaction products. In the case of zinc hydroxide the high efficiency for NO 2 retention was linked to: (1) developed porosity, (2) presence of OH groups in the zinc hydroxide phase, (3) photocatalytic activity of Zn(OH) 2 . That activity was enhanced when graphite oxide, being able to activate oxygen and spatially separate the electronÀhole pairs, was added as a composite component. Graphite oxide also contributes to the high dispersion of active terminal OH groups. After dehydroxylation, the resulting ZnO loses its activity to retain NO 2 on the surface. On the other hand, the activity of the composite increases owing to the combined effects of zinc oxide photoactivity, high dispersion of an inorganic phase, separation of electronÀhole pairs, increase in electronic conductivity, reactive carbonaceous component, and the presence of OH groups on partially reduced graphene phase.

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“…DFT cluster models and periodic boundary condition calculations indicated that alkaline oxides such as CaO and BaO chemisorb NO species [23][24][25]. Moreover, adsorption of NO 2 /NO 2 , NO/NO 2 , or NO/NO molecular pairs was studied, and it was found that a cooperative effect contributes to increase adsorption energy of the pair [26][27][28]. Although NO and NO 2 are both radicals, thereby being highly reactive, considering the large availability of magnesium oxides for catalytic applications, we could ask if the TNT molecule, having three nitro groups, could favorably adsorb on a MgO (001) surface through a cooperative effect thus leading to possible deactivation.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Trinitrotoluene on a MgO(001) Surface Including Surface Relaxation Effects

Guerra

Borges

2012

Journal of Chemistry

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A thorough investigation of 2,4,6-trinitrotoluene (TNT) adsorption on a MgO(001) surface was carried out using density functional theory (DFT) combined with periodic boundary conditions. Four different initial orientations of the TNT molecule, adsorbed on two different representations of the MgO(001) surface, were investigated. In the first surface representation, there were two fixed layers of atoms and in the second the surface had three layers, with the uppermost fully relaxed in geometry optimizations. Electron density difference maps for each case were computed and provided a detailed picture of the interactions. The results showed a physical adsorption process for both surface representations. In the most favorable situation—TNT adsorbed on the surface with three layers—the computed adsorption energy was −9.89 kcal/mol. The importance of allowing the uppermost layer of the surface to fully relax upon molecular desorption was shown.

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Characterization of adsorption trends of NO2, nitrite, and nitrate on MgO terraces

Cited by 18 publications

References 35 publications

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Interactions of NO₂ with Zinc (Hydr)oxide/Graphene Phase Composites: Visible Light Enhanced Surface Reactivity

Adsorption of Trinitrotoluene on a MgO(001) Surface Including Surface Relaxation Effects

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Characterization of adsorption trends of NO2, nitrite, and nitrate on MgO terraces

Cited by 18 publications

References 35 publications

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Removal of Nitrate and Nitrite Anions from Wastewater Using Activated Carbon Derived from Rice Straw

Interactions of NO2 with Zinc (Hydr)oxide/Graphene Phase Composites: Visible Light Enhanced Surface Reactivity

Adsorption of Trinitrotoluene on a MgO(001) Surface Including Surface Relaxation Effects

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Interactions of NO₂ with Zinc (Hydr)oxide/Graphene Phase Composites: Visible Light Enhanced Surface Reactivity